I had a friend who turned out to be a trans man a few years ago and they did a caryotype before transitioning (or for whatever reason I don't remember, that was back in 2016-17 or so) and it was found out that they were a "true trans" (their words), so probably intersex. Felt like a guy since childhood, but lived as female for a long time, until age 25-ish. Even when they were female-presenting, their voice was super deep for a woman, and I wasn't surprised at all when they turned out to be a trans male. Even with super long hair they were quite masculine in the manners, in... the vibe. But such cases seem to be quite rare.
A former schoolmate of mine transitioned to male starting around 2019 or so but has always given me the impression, unlike my friend, that their "trans-ness" is more rooted in psychological issues rather than an actual chromosomic thing. They're always tweeting and venting about their mental issues and such, and apparently suffer from BPD, anxiety, and probably a couple others I didn't see. It's really a whole different vibe. I still feel the girl inside of them if that makes sense, and I'm afraid they might be a future detransitioner. But I hope not. I'd be sad for them if that were the case given they had top surgery and all